>OK, fair enough. I can't imagine that happening since the software I write is highly customized for specific tasks and runs in a single environment. I'm lucky if my clients know how to power on the workstation (most don't turn them off at night for that reason!) much less change a color scheme. So, going back to the original question: how do you create a mask for a magenta background and use it on a command button?

I see that Carlos already gave you the details on creating a .MSK file with Paint.